Giant platelets are larger than an RBC while large platelets are just larger than normal platelets.

Seen in Myelodysplastic and Myeloproliferative Disorders.

Clots on a slide can be found on the feathered edge as they are larger. They look like purple “goobers” with some platelets visible. Unlike in EDTA clumping, fibrin strands can usually also be seen.

Platelet count appears falsely decreased or is accompanied by flags, making this an unacceptable specimen. It is important to note that a large clot in the cap or side of the tube , may not appear on a slide. This is why any suspect specimens should always be visually inspected for clots.

EDTA-dependent platelet clumping may be seen as large platelets clumps at feathered edge or smaller clumps in peripheral of smear depending on severity. Unlike in clots, individual platelets can be counted.

EDTA clumping can cause the analyzer to underestimate platelets. It is caused by an in vitro reaction of the platelets with the anticoagulant in lavender tubes. To fix this issue and get an accurate platelet count, labs usually have a protocol to recollect the specimen in a sodium citrate tube.